Rather than have a Gore-beast pulling a chariot in a conventional manner, I think that a massive resurrected swamp-grub, enslaved in undeath by the foul magicks of Nurgle, toting a Howdah would be very in theme with a highly mutated Nurgle army.
The body of this model is made from a tinfoil armature and layered with super-sculpy and Apoxie-sculpt. The details are primarily done with Greenstuff.
Check out my insect leg tutorial to see how the legs were achieved: Sculpting Insect Legs
The crew for this beast are coming together. More on them later!